When I purchased my 2007 Ford Edge SEL it was from Dealer Stock so I did not have theoption of which radio to choose.  After a few weeks I decided to put in a Factory Ford Navigation Radio rather than go the aftermarket route. 
  
I went on ebay and pruchased a unit which was from a 06/07 Explorer or Mountaineer, which has a Ford Part # 6L2T-18K931-BC. The Edge Ford Part #'s are 7T4T-18K931-BA and 7T4T-18K931-AG which are Premium or Audiophile units and would require no reprogramming to match the vehicle.  I have seen one of these part #'s on an ebay auction. I am also attaching a PDF file that I used to help me with my radios search on ebay to make sure that I was getting the right plug configuration and mounting type.  
  
The radio did not come with an antenna, so that was my next search. First I had to find the part # which specifically for the Edge is 7T4Z-10E893-A, although 8G1Z-10E893-A will also work.  I found the antenna on Amazon.com through Troy Ford by entering in the base part # 10E893 in the search window. 
  
The whole installation takes maybe 30 minutes and it is all plug and play.  I will post pictures in the near future of the installation. 
  
The best part about it is that all the factory items cost me less than buying a Pioneer or Kenwood Nav Radio!  I am also going to change out the factory speakers with Kenwood speakers front and rear. 
  
I hope this helps for anyone else looking to perform a similar upgrade to their Edge! 
radio_guide.pdf